Lightning Damage

2011

Several million volts can flow from a lightning strike! So no amount of equipment can guarantee absolute protection from a direct (or near direct) strike. However, installing SPD's and implementing other measures can reduce the impact. Adequate grounding and bonding systems help minimize the potential for damage and will reduce the risk of electric shock.

According to IS10101 when wiring a domestic installation SPD's must be installed unless a risk assessment is generated that states that they are not necessary. Due to the fact that these devices are relatively cheap I don't expect that many will generate a RA to avoid installing SPD's.

Depending on the outcome of a Risk Assessment larger installations (not domestic) may have external lightning protection systems installed, these would be certified to EN 62305 (Protection against lightning). These systems typically include "air terminations" (lightning rods), multiple "down conductors", and grounding systems to intercept the lightning strike and provide a controlled path for the lightning current to flow (less) harmlessly into the ground.

windowcills

https://www.boards.ie/discussion/comment/120738154#Comment_120738154

I dont feel like i really "own" something until i have fixed it in someway

10-10-20

Well I have it first-hand here now. Lightening strike very close to the house yesterday appears to have come though the Virgin Media cable and into the house, crossed over to my ethernet network and took out the VM box, attached TV, routers and switches and network cards on some systems. So effectively many of the devices which had a potential between the wired ethernet and the AC was damaged. No AC devices which were standalone (without an ethernet cable) were affected. 😫 No SPD on the AC mains-in was going to prevent that. One other person has a damaged Sky box, that's all of the other damage that I know of.

The Continental Op

Has anyone any experience of lightning hitting external ethernet cables? Luckily while I've installed a good few outside I've never had a lightning strike, even used properly earth In Line Surge Protectors like these however no idea if they actually work. I've read a few reports of them not working but did they reduce inevitable damage or do no good at all, were they even installed correctly? Problem is most of the affordable ones have the made in china look about them that always leads to questions.

I'd be a little dubious of ANY SPD protecting from a direct hit. I've seen a coms tower that got hit and you could see where the cables were in the ground by the trench blown out and burnt grass from the strike. I also seen trees vaporised by lightning strikes (missed one by a couple of minutes it left timber thrown 100 meters or more from the strike). However I'm sort of prepared to believe an SPD device might help except in a worse case scenario and might also help in a worse case by preventing more damage?

Antenna

https://www.boards.ie/discussion/comment/120766893#Comment_120766893

it would be a big advantage of a changeover to fibre-to-the-home. The fibre cable is going to be non-conductive of electricity with the benefit that this cannot happen!

10-10-20

https://www.boards.ie/discussion/comment/120769326#Comment_120769326

True, and it's making me think about fibre between my switches too.

CelticRambler

https://www.boards.ie/discussion/comment/120768114#Comment_120768114

I'm in a different part of the world (as you know!) and the main board is fitted with a surgeprotector that gets regular exercise. A couple of weeks ago, a very local strike sent a surge through the power cables and tripped the main supply switch, so there was no external feed to the house. A few minutes later, while I was still using a mouse connected to the laptop (on battery, but still plugged into the wall socket) an even localler strike sent a shock up my arm and tripped the main switch for the rail on which that circuit hangs.

I assume it can only have been caused by an induced current in the in-house cables as the lightning passed overhead, seeing as the laptop was effectively offline in every other respect. If 60cm stone walls can't protect against that, I reckon an outdoor ethernet cable would be just as vulnerable (although possibly more likely to melt first?)

kirk.

From the farming forum

I presume you'd need type 1 spd at the shed board to prevent lightning damage coming in on the fence wiring .That's if you're not using the above.

The literature only shows SPD1 at the origin assuming lightning strike coming in on the supply side